A health directorate survey has found the larvae of Aedes aegypti mosquitoes in 18 percent of homes in Dhaka, while the presence of the dengue disease-spreading mosquitoes in 5 percent of homes is considered risky.
Until Jun 27, hospitals across the country have recorded 7,754 cases with a death toll of 47. According to the health directorate, the number of cases and deaths due to dengue fever has never been so high halfway through the year.
Experts at the Directorate General of Health Services fear a further uptick in dengue cases this year. Startled by the result of the recent study, surveyors feared that the dengue epidemic this year was likely to hit the country much harder than it has ever before.
The officials said a better method of dealing with the issue would be to prevent dengue from spreading rather than raising the number of patient beds in hospitals, and the responsibility must be taken at the individual level.
The study was carried out across 98 wards in Dhaka from Jun 18-27. Along with identifying the breeding grounds of mosquitoes responsible for dengue and chikungunya diseases, it mapped out the density of mosquitoes and larvae.
The DGHS revealed the findings of the first eight days of the survey.
Until Jun 25, as many as 453 of 2,511 homes were infested with Aedes larvae, while 625 of 2,738 containers had larvae inside, according to the findings.
It showed that 210 of 962 sample houses were infested with Aedes mosquitoes in Dhaka North City, while 243 of 1,549 homes in Dhaka South City were at risk as well.
The DNCC recorded a House Index threshold of 21.8 percent and a Breteau Index of 28.79. In Dhaka South, HI stood at 15.7 percent and BI at 22.47 percent. BI and HI exceeding 20 percent and 5 percent, respectively, are risky, according to experts.
Entomologist Kabirul Bashar, a professor of zoology at Jahangirnagar University, was involved in the survey. Where a House Index above 5 percent is considered dangerous, it is over 18 percent in Dhaka,” he said.
“From our experience dengue outbreak has occurred wherever the House Index measures above 5 percent. The mosquito density is chiefly measured using Breteau Index.”
The risks of dengue are much higher than in the previous years. “We fear that the dengue infections will be much more this year than before. We’re finding a higher density of mosquitoes this year at the field level,” Kabirul said.
“The Aedes mosquitoes carrying dengue have been acting way more aggressive this time even before the arrival of monsoon. I think they will try to be more aggressive in August-September,” he added.
Dr Nazmul Islam, director of disease control at the DGHS, seconded Kabirul’s projections.
“Dengue-related complications increase when the number of cases rises. If we don’t want patients in critical condition and people dying, then we must find the mosquitoes’ breeding grounds and exterminate them,” he said.
“Additionally, citizens have to come forward to properly manage waste materials, and keep their yards clean, only then we might go through this season without any major incident. Otherwise, things will go out of control.”
ON THE GROUND
Following the start of the survey, 21 teams spread out every day to inspect different areas. Each team of three surveyed 15 houses, totalling 315 homes being studied per day. The sites included residential, under-construction, multi-storey, single-storey homes, open spaces and slums.
The surveyors found larvae at nine of 15 houses in Moghbazar, Dilu Road and Eskaton, three major hotspots, on Jun 19. That day, 74 houses out of 315 surveyed were found as hosting Aedes larvae.
On Tuesday, four houses of the 15 surveyed were found buzzing with Aedes mosquitoes and larvae.
In a multi-floor Gulshan house at Road No. 136, the bottom floor seemed well-organised and without any infestation. However, drums left open at the border of the house and in the middle were identified as breeding grounds.
Similarly, another two-storey building on the same street had some flower pots where the surveyors found larvae.
The owner of the house, Nurunnahar Rahman, who resides in the house with a maid, said she had instructed the gardener to carefully drain any accumulating water but the gardener went on Eid holidays two days ago.
As a result, no one had been taking care of the plants, which may have caused it to happen. Yet she had no idea that larvae could form so quickly, Nurunnahar said.
“I was always very careful about dengue. But how it happened here so quickly amazed me. I’m making arrangements to spray medicines here and will keep an eye out so that it doesn’t happen anywhere else again.”
An official of the health directorate, who asked not to be named, said: “We found nine houses infested with larvae among 15 in Gulshan. On the first day, we identified 60 houses after going through 315 of them and found larvae. The state of Gulshan and Banani is not good this time. In fact, it’s pretty bad.”
Dhaka North Mayor Atiqul Islam on Tuesday said the city corporation was doing its best to prevent infestation alongside efforts to raise people’s awareness.
“I’ve repeatedly said that it’s not possible to curb dengue infections by the city corporations alone. The citizens must step up as well. How can they do that? They have to get rid of water accumulating for more than three days.”
Sheikh Fazle Noor Taposh, mayor of Dhaka South, mentioned that people were not vigilant against the disease at all, so the authorities will carry out a thorough campaign to kill mosquitoes.
“We will strengthen the mobile court operations and fine people for offences.”